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The purpose of this study was to analyze the different soils in Denton, Texas. For the purpose of this study, the soils of Denton County are divided into three general groups with respect to origin: 1)those formed in place by the weathering of consolidated rocks, 2) those formed from the weathering of unconsolidated rocks, and 3) alluvial soils. A chemical analysis of representative samples of Bell Clay, Kirvin fine sandy loam, and San Saba clay has been made, and shown to have a strict correlation with their respective geological origins.

There is growing concern over the environmental and human health impacts of chemical contaminants in agricultural systems. The environmental persistence of veterinary antibiotics applied to agricultural fields during manure fertilization could lead to increased antibiotic resistance. New generation, neonicotinoid pesticides pose a threat to aquatic ecosystem health due high water mobility and increased potential for non-target exposure. The objectives of this research were to develop a sensitive, analytical method for quantification of pirlimycin (PLY) in soils to be used in field research and determine the ability of second-generation neonicotinoids to move through soil when applied as a seed coating using a greenhouse study. Liquid-solid extraction of PLY from soil using (1:6, v/v) ammonium hydroxide/methylene chloride produced good PLY recovery (67-140%). Liquid-chromatography coupled with tandem mass-spectrometry for instrumental analysis provided good sensitivity with minimal matrix interferences. The mass balance distribution of neonicotinoid treatment coated onto corn seeds was determined in plant and soil samples for a single pot after 3 weeks of growth. A large percent (83-87%) of initial pesticide coating applied to seed was un-detected in plant in soil. Of the detected portion of neonicotinoid treatment, between 96-98% was observed to move out into the soil. This suggests the potential for long-range transport of seed-coated neonicotinoids. / Master of Science / There is growing concern over the environmental and human health impacts of chemical contaminants in agricultural systems. The environmental persistence of veterinary antibiotics applied to agricultural fields during manure fertilization could lead to increased antibiotic resistance. New generation, neonicotinoid pesticides pose a threat to aquatic ecosystem health due high water mobility and increased potential for non-target exposure. The objectives of this research were to develop a sensitive, analytical method for quantification of pirlimycin (PLY) in soils to be used in field research and determine the ability of second-generation neonicotinoids to move through soil when applied as a seed coating using a greenhouse study. Liquid-solid extraction of PLY from soil using (1:6, v/v) ammonium hydroxide/methylene chloride produced good PLY recovery (67-140%). Liquid-chromatography coupled with tandem mass-spectrometry for instrumental analysis provided good sensitivity with minimal matrix interferences. The mass balance distribution of neonicotinoid treatment coated onto corn seeds was determined in plant and soil samples for a single pot after 3 weeks of growth. A large percent (83-87%) of initial pesticide coating applied to seed was un-detected in plant in soil. Of the detected portion of neonicotinoid treatment, between 96-98% was observed to move out into the soil. This suggests the potential for long-range transport of seed-coated neonicotinoids.

O enxofre no solo pode ser encontrado em duas formas básicas como S-Inorgânico e S-Orgânico. O enxofre na forma inorgânica (S-Sulfato) pode estar prontamente disponível à planta, mas o enxofre orgânico é responsável por 95% do enxofre total na maioria dos solos. Com o objetivo de quantificar o sulfato disponível do solo utilizou-se como extrator solução de acetato de amônio em ácido acético. A eficiência da oxidação do S-Orgânico à S-Inorgânico, para determinação de S-Total em amostras de solo, foi avaliada com o emprego de métodos de oxidação por via úmida e seca. Para a quantificação do S-Total e S-Sulfato disponível foi desenvolvido um sistema automatizado de análise em fluxo (FIA) empregando multicomutação e amostragem binária. Os resultados das determinações de S-Total e de Sulfato disponível mostraram-se concordantes entre os procedimentos analíticos avaliados, sistema automatizado e o manual (convencional). A utilização de material marcado (K234SO4), teve como finalidade a validação do método de determinação de S-Total e isotópica de S nas amostras de solo. Com os resultados obtidos no experimento pode-se verificar que o processo de conversão de S-Orgânico à S-Inorgânico utilizando o método de oxidação alcalina, via seca, foi adequado. Com os resultados da determinação isotópica de S (% em átomos de 34S) do experimento empregando material enriquecido em 34S(k2SO4), pode-se calcular que o erro analítico foi em média 1,1 %. Este foi considerado baixo tendo em vista que o processo envolve varias etapas e dois procedimentos analíticos complexos / Sulphur in soil may be found under two basic forms; Inorganic-S and Organic-S. Sulphur under inorganic form (Sulphate-S) may be available to plant, however organic sulphur is responsible for 95 % of total sulphur in the most of soils. Aiming quantifies the available sulphur in soil, ammonium acetate plus acetic acid extractor solution was used. Efficiency of Organic-S oxidation to form Inorganic-S for Total-S determination in soil samples was evaluated applying oxidation reaction by wet and dried methods. A flow injection analysis (FIA) automatic system exploring multi-commutation and binary sample techniques was development for determination of Total-S and available Sulphate-S. Results of Total-S and available Sulphate were in agreement with analytical procedures evaluated, automatic and conventional systems. Use of labeled material (K234SO4) aimed to validate the method for Total-S and isotopic S determination in soil samples. Obtained results in experiments showed that the conversion process of Organic-S to Inorganic-S using alkaline oxidation reaction by dried method was appropriated. Based on results obtained in S isotopic determination (% in atoms of 34S) by applied experiment using material enriched on 34S(k2SO4), was possible calculate that the analytical error was about 1.1 %. This result was considered low considering quantity of involved steps in process and complexity of analytical process

O enxofre no solo pode ser encontrado em duas formas básicas como S-Inorgânico e S-Orgânico. O enxofre na forma inorgânica (S-Sulfato) pode estar prontamente disponível à planta, mas o enxofre orgânico é responsável por 95% do enxofre total na maioria dos solos. Com o objetivo de quantificar o sulfato disponível do solo utilizou-se como extrator solução de acetato de amônio em ácido acético. A eficiência da oxidação do S-Orgânico à S-Inorgânico, para determinação de S-Total em amostras de solo, foi avaliada com o emprego de métodos de oxidação por via úmida e seca. Para a quantificação do S-Total e S-Sulfato disponível foi desenvolvido um sistema automatizado de análise em fluxo (FIA) empregando multicomutação e amostragem binária. Os resultados das determinações de S-Total e de Sulfato disponível mostraram-se concordantes entre os procedimentos analíticos avaliados, sistema automatizado e o manual (convencional). A utilização de material marcado (K234SO4), teve como finalidade a validação do método de determinação de S-Total e isotópica de S nas amostras de solo. Com os resultados obtidos no experimento pode-se verificar que o processo de conversão de S-Orgânico à S-Inorgânico utilizando o método de oxidação alcalina, via seca, foi adequado. Com os resultados da determinação isotópica de S (% em átomos de 34S) do experimento empregando material enriquecido em 34S(k2SO4), pode-se calcular que o erro analítico foi em média 1,1 %. Este foi considerado baixo tendo em vista que o processo envolve varias etapas e dois procedimentos analíticos complexos / Sulphur in soil may be found under two basic forms; Inorganic-S and Organic-S. Sulphur under inorganic form (Sulphate-S) may be available to plant, however organic sulphur is responsible for 95 % of total sulphur in the most of soils. Aiming quantifies the available sulphur in soil, ammonium acetate plus acetic acid extractor solution was used. Efficiency of Organic-S oxidation to form Inorganic-S for Total-S determination in soil samples was evaluated applying oxidation reaction by wet and dried methods. A flow injection analysis (FIA) automatic system exploring multi-commutation and binary sample techniques was development for determination of Total-S and available Sulphate-S. Results of Total-S and available Sulphate were in agreement with analytical procedures evaluated, automatic and conventional systems. Use of labeled material (K234SO4) aimed to validate the method for Total-S and isotopic S determination in soil samples. Obtained results in experiments showed that the conversion process of Organic-S to Inorganic-S using alkaline oxidation reaction by dried method was appropriated. Based on results obtained in S isotopic determination (% in atoms of 34S) by applied experiment using material enriched on 34S(k2SO4), was possible calculate that the analytical error was about 1.1 %. This result was considered low considering quantity of involved steps in process and complexity of analytical process

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.

Abstract Despite tightened environmental legislation, spillages of petroleum products remain a serious problem worldwide. The environmental impacts of these spillages are always severe and reliable methods for the identification and quantitative determination of petroleum hydrocarbons in environmental samples are therefore needed. Great improvements in the definition and analysis of total petroleum hydrocarbons (TPH) were finally introduced by international organizations for standardization in 2004. This brought some coherence to the determination and, nowadays, most laboratories seem to employ ISO/DIS 16703:2004, ISO 9377-2:2000 and CEN prEN 14039:2004:E draft international standards for analysing TPH in soil. The implementation of these methods, however, usually fails because the reliability of petroleum hydrocarbon determination has proved to be poor. This thesis describes the assessment of measurement uncertainty for TPH determination in soil. Chemometric methods were used to both estimate the main uncertainty sources and identify the most significant factors affecting these uncertainty sources. The method used for the determinations was based on gas chromatography utilizing flame ionization detection (GC-FID). Chemometric methodology applied in estimating measurement uncertainty for TPH determination showed that the measurement uncertainty is in actual fact dominated by the analytical uncertainty. Within the specific concentration range studied, the analytical uncertainty accounted for as much as 68–80% of the measurement uncertainty. The robustness of the analytical method used for petroleum hydrocarbon determination was then studied in more detail. A two-level Plackett-Burman design and a D-optimal design were utilized to assess the main analytical uncertainty sources of the sample treatment and GC determination procedures. It was also found that the matrix-induced systematic error may also significantly reduce the reliability of petroleum hydrocarbon determination. The results showed that strict implementation of the ISO and CEN draft standards is necessary owing to the method dependence of the analyzed parameter. Care should be taken to ensure that the methods used for petroleum hydrocarbon determination are comprehensively validated, and that routine quality control is carried out in order to ensure that the validation conclusions are applicable in the daily work.

Made available in DSpace on 2014-06-11T19:33:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-07-10Bitstream added on 2014-06-13T18:45:43Z : No. of bitstreams: 1 yagi_r_dr_jabo.pdf: 413490 bytes, checksum: a38c7eec6330f4c0a6acf335dd1ae765 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Foram avaliados 16 índices químicos de disponibilidade de N para a cultura do milho em 22 solos do Estado de São Paulo. Os índices químicos de disponibilidade de N foram matéria orgânica, N total, N inorgânico e N extraído com KMnO4/NaOH, H2O2/MnO, tampão fosfato-borato, K2Cr2O7/H2SO4, Na2Cr2O7.2H2O/H2SO4 e KCl a quente/MgO ou NaOH. Métodos biológicos de incubação de solo em condições aeróbias (35ºC por 30 semanas) e anaeróbias (40ºC por 7 dias), e experimento em casa de vegetação tendo o milho como planta-teste foram utilizados como padrões de referência para os índices químicos. Os métodos de extração do N disponível com KCl a quente/MgO e Na2Cr2O7.2H2O/H2SO4 apresentaram as melhores correlações com índices biológicos de mineralização ou disponibilidade de N. Na calibração destes métodos a partir de dois experimentos em vasos e em casa de vegetação, foram obtidos valores de nível crítico (NC) de N disponível que variaram de 33,0 a 35,0 mg dm-3 e de 430 a 525 mg dm-3, respectivamente. A partir destes valores de NC foram calculadas doses de N recomendadas (DR), com base em análise de N disponível em amostras de solo iniciais de três experimentos a campo e em experimento de incubação de solo em laboratório. A calibração dos métodos de análise para Nd do solo permitiu a obtenção do nível crítico de 35,0 mg dm-3 para o método do KCl a quente, como limite das classes de resposta e não resposta à adubação nitrogenada para a cultura do milho. Não foi possível calibrar o método de determinação de Nd com solução sulfocrômica. / Were evaluated 15 chemical indices for N availability for corn crop in 22 Sao Paulo State soils. The chemical indices of N availability were soil organic matter, total N, inorganic N and N extracted with KMnO4/NaOH, H2O2/MnO, phosphate-borate buffer, K2Cr2O7/H2SO4, Na2Cr2O7.2H2O/H2SO4, hot KCl/MgO or NaOH. Biological methods of soil incubation under aerobic conditions (35ºC for 30 weeks) and anaerobic (40ºC for 7 days), and experiment in a greenhouse taking the corn as test-plant were used as benchmarks for the chemical indices. The methods of extracting the N available with hot KCl/MgO and Na2Cr2O7.2H2O/H2SO4 showed the best correlation with N biological mineralization or availability. In the calibration of these methods from two experiments in pots and in greenhouse, were obtained critical level (CL) values of N available that ranged from 33.0 to 35.0 mg dm-3 and 430 to 525 mg dm-3, respectively. From these CL values were recommended N rates (NR), based on N available analysis in initial soil samples from three experiments in the field and in soil incubation in laboratory. In just one of the field experiments was possible to calculate NR of maximum economic efficiency, which were compared with NR. The calibration of the methods of analysis for N available soil allowed the achievement of CL of 35.0 mg dm-3 for the hot KCl method, as the limit of the classes of response and no response to nitrogen fertilization to corn cultivation. It was not possible to calibrate the method of determining of N available with sulfocromic solution.

Resumo: Foram avaliados 16 índices químicos de disponibilidade de N para a cultura do milho em 22 solos do Estado de São Paulo. Os índices químicos de disponibilidade de N foram matéria orgânica, N total, N inorgânico e N extraído com KMnO4/NaOH, H2O2/MnO, tampão fosfato-borato, K2Cr2O7/H2SO4, Na2Cr2O7.2H2O/H2SO4 e KCl a quente/MgO ou NaOH. Métodos biológicos de incubação de solo em condições aeróbias (35ºC por 30 semanas) e anaeróbias (40ºC por 7 dias), e experimento em casa de vegetação tendo o milho como planta-teste foram utilizados como padrões de referência para os índices químicos. Os métodos de extração do N disponível com KCl a quente/MgO e Na2Cr2O7.2H2O/H2SO4 apresentaram as melhores correlações com índices biológicos de mineralização ou disponibilidade de N. Na calibração destes métodos a partir de dois experimentos em vasos e em casa de vegetação, foram obtidos valores de nível crítico (NC) de N disponível que variaram de 33,0 a 35,0 mg dm-3 e de 430 a 525 mg dm-3, respectivamente. A partir destes valores de NC foram calculadas doses de N recomendadas (DR), com base em análise de N disponível em amostras de solo iniciais de três experimentos a campo e em experimento de incubação de solo em laboratório. A calibração dos métodos de análise para Nd do solo permitiu a obtenção do nível crítico de 35,0 mg dm-3 para o método do KCl a quente, como limite das classes de resposta e não resposta à adubação nitrogenada para a cultura do milho. Não foi possível calibrar o método de determinação de Nd com solução sulfocrômica. / Abstract: Were evaluated 15 chemical indices for N availability for corn crop in 22 Sao Paulo State soils. The chemical indices of N availability were soil organic matter, total N, inorganic N and N extracted with KMnO4/NaOH, H2O2/MnO, phosphate-borate buffer, K2Cr2O7/H2SO4, Na2Cr2O7.2H2O/H2SO4, hot KCl/MgO or NaOH. Biological methods of soil incubation under aerobic conditions (35ºC for 30 weeks) and anaerobic (40ºC for 7 days), and experiment in a greenhouse taking the corn as test-plant were used as benchmarks for the chemical indices. The methods of extracting the N available with hot KCl/MgO and Na2Cr2O7.2H2O/H2SO4 showed the best correlation with N biological mineralization or availability. In the calibration of these methods from two experiments in pots and in greenhouse, were obtained critical level (CL) values of N available that ranged from 33.0 to 35.0 mg dm-3 and 430 to 525 mg dm-3, respectively. From these CL values were recommended N rates (NR), based on N available analysis in initial soil samples from three experiments in the field and in soil incubation in laboratory. In just one of the field experiments was possible to calculate NR of maximum economic efficiency, which were compared with NR. The calibration of the methods of analysis for N available soil allowed the achievement of CL of 35.0 mg dm-3 for the hot KCl method, as the limit of the classes of response and no response to nitrogen fertilization to corn cultivation. It was not possible to calibrate the method of determining of N available with sulfocromic solution. / Orientador: Manoel Evaristo Ferreira / Coorientadora: Mara Cristina Pessôa da Cruz / Banca: José Ricardo Mantovani / Banca: Tsuioshi Yamada / Banca: Heitor Cantarella / Banca: Wanderley José de Melo / Doutor

O conhecimento do comportamento físico-hídrico do solo é fundamental para sua caracterização. Dentre elas, a determinação da curva de retenção de água é o processo que costuma ser mais oneroso e demorado. Várias tentativas estão sendo estudadas no sentido de minimizar custo e tempo para a obtenção desta curva. A escolha do número e da combinação de pontos, ou seja, dados de umidade e correspondente tensão da água no solo, utilizados para a determinação da curva de retenção, normalmente é feita de forma arbitrária, contudo, a demora na obtenção da curva de retenção, aliada ao valor considerado alto para pequenos irrigantes, são na maioria das vezes, um empecilho para que o agricultor realize esta análise. O objetivo deste trabalho foi definir o menor número e a melhor combinação de pares de umidade e tensão de água no solo que resulte na descrição de uma curva de retenção de água do solo confiável. Para a realização da pesquisa, foram utilizados dois tipos de solos com granulometrias distintas, (arenoso e argiloso). Foram realizadas nove repetições, para cada tipo de solo, as quais foram submetidas a diferentes tensões pelo método da câmara de Richards e ajustadas pelo modelo de van Genuchten. Realizaram-se curvas contendo 4, 5, 7, 8, 9, 10 e 13 pontos de tensão, sendo que a curva que contem 13 pontos foi adotada neste estudo como referência (A1) na comparação com as demais. A análise estatística foi gerada inicialmente sobre os dados brutos das umidades do solo observadas para todas as repetições, calculando-se os coeficientes de variação para os parâmetros do modelo de van Genuchten. Posteriormente, entre os dados observados e ajustados pelo modelo, foram determinados índices estatísticos comparativos. Finalmente, os parâmetros obtidos de vários pares de umidade e correspondente tensão de água no solo obtidos na câmara Richards foram comparados aos parâmetros equivalentes da curva referência (A1) e submetidos à análise de variância (teste F), e suas médias comparadas pelo teste de Scott-Knott a 5%. A curva de retenção de água no solo com 7 pontos, elaborada com as tensões 0, 40, 100, 300, 1.000, 5.000 e 15.000 hPa, foi a que mais se aproximou da curva de referência A1, não apresentando diferença estatística em nenhum dos parâmetros do modelo. / The knowledge of the soil hydrophysical behavior is critical for characterizing its physical properties. Among them, the determination of the soil water retention curve is often the most expensive and the most time consuming. Many attempts have been tried in order to minimize the cost and the time to obtain this curve. The choice of number and combinations of points to be taken, i.e., water content and its corresponding water potential in soil, used to determine the soil water retention curve, is usually made arbitrarily, however, the delay in obtaining the curve, coupled with the cost considered high to small irrigators, are mostly an obstacle for the farmer to carry out this analysis. The objective of this work was to define the smallest number and the optimal combination of water content and water potential pairs that result in a trustable soil water retention curve. To carry out this research, two types of soils with contrasting textures were used (sandy and clay soil). For each type of soil, nine repetitions were submitted to different tensions by the Richards chamber method and adjusted by the equation of van Genuchten. Curves with 4, 5, 7, 8, 9, 10 e 13 tension points were made, taking the 13-point curve as a standard (A1) in comparison to the others. Initially, the statistical analysis was performed on the raw data of the observed water contents for all the repetitions, calculating the variation coefficient for the van Genuchten equation parameters. Subsequently, statistical indices of comparison were used between the observed and adjusted data. Lastly, the obtained parameters for different pairs of water content and its corresponding water potential in Richards\' chamber were compared to the equivalent parameters of the standard curve (A1) and submitted to the analysis of variance (F test), and their mean values were compared by the Scott-Knott test (5% of probability). The 7-point soil water retention curve, using the tensions of 0; 40; 100; 300; 1,000; 5,000 e 15,000 hPa, was the closest one to the standard curve A1, showing no statistical difference in any parameters of the model.